<script lang="ts" setup name="XtxCarousel">
import { BannerItem } from '@/types/data'
import { onBeforeUnmount, onMounted, PropType, ref } from 'vue'
// js
// defineProps({
//   slides: {
//     type: Array as PropType<BannerItem[]>,
//     required: true
//   }
// })

// ts 
// vite.config.js进行配置
const { slides, autoPlay = false, duration = 1000  } = defineProps<{
  slides: BannerItem[]
  // 自动轮播
  autoPlay?:boolean
  // 间隔时长
  duration?:number
}>()

// 定义高亮的下标 默认是0
const active = ref(0)
let timer = -1 // 定时器ID

// 左右箭头切换图片
// 上一张
const onPrev = () => {
  if (active.value === 0 ) {
    active.value = slides.length - 1
  } else {
    active.value -- 
  }
}
// 下一张
const onNext = () => {
  // 0 1 2 3 4 
  if (active.value === slides.length - 1 ){
    active.value = 0
  } else {
    active.value ++ 
  }
}

// 鼠标移入 - 关闭定时器
const stop = () => {
  clearInterval(timer)
}
// 鼠标移出 - 开启定时器
const play = () => {
  // 自动轮播
  // 模块环境下. 定时器/延时器会被识别成node环境下的定时器延时器
  // 浏览器环境下 -> window.set...
  if (!autoPlay) return
  timer = window.setInterval(() => {
    // console.log('轮播图进行中....');
    onNext()
  }, duration)
}

onMounted(() => {
  play()
})
onBeforeUnmount(() => {
  stop()
})
</script>

<template>
<!-- fade  
      控制图片的显示和隐藏
  -->
<!-- active
     控制小圆点的高亮 
-->
  <div class="xtx-carousel" @mouseenter="stop" @mouseleave="play">
    <!-- 轮播主体 -->
    <ul class="carousel-body">
      <li class="carousel-item" :class="{ fade: active === index }"  v-for="(item, index) in slides" :key="item.id">
        <RouterLink :to="item.hrefUrl">
          <img
            :src="item.imgUrl"
            alt=""
          />
        </RouterLink>
      </li>
    </ul>
    <!-- 左右箭头 -->
    <a href="javascript:;" @click="onPrev" class="carousel-btn prev"
      ><i class="iconfont icon-angle-left"></i
    ></a>
    <a href="javascript:;" @click="onNext" class="carousel-btn next"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <!-- 小圆点的指示器 -->
    <div class="carousel-indicator">
      <span
        :class="{ active: active ===  index}"
        v-for="(item, index) in slides" :key="item.id"
        @mouseenter="active = index"
    ></span>
    </div>
  </div>
</template>

<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>